The neonatal immune system has been traditionally thought to be immature and functionally dependent upon maternal antibodies for protection against pathogenic organisms. In fact, Burnet, F. M. and Fenner, F., Macmillan, Melbourne, The Production of Antibodies, 102-105 (1949) proposed that exposure of the human neonate to antigens including infectious agents, would induce a state of specific immunological tolerance to those antigens. Medawar and colleagues (Billingham, R. E. et. al., Nature, 172:603 (1952)) later provided experimental evidence for this hypothesis by showing that newborn mice exposed to foreign white blood cells would accept foreign tissues from the same donor as adults.
Effective methods for inducing immunity to pathogens in the neonatal immune system are needed.